The present invention relates generally to placing apparatus, and more particularly, to a rotary placer which selectively picks up, transfers and places a blank from a fixed magazine wherein package blanks are contained in stacked arrangement to an assembly position which typically involves a conveyor.
Rotary placers typically include one or more arms which rotate about a central axis. Vacuum cups attached to the ends of the arms pick up a carton blank from a pick position at the magazine, transfer the carton blank by rotation of the arm, and disengage the carton blank at a place position on the conveyor or other apparatus for assembly. In many of these devices the carton blanks are engaged and disengaged by a wiping or sweeping motion as the vacuum cups rotate past the pick and place positions.
However, it is desirable for the vacuum cups to move in substantially straight line in and out motion at the pick and place positions. The straight-line motion at the pick position ensures that facing areas of the carton blank will be initially separated to facilitate further squaring of the blank at the assembly or place position and also to ensure that improper bending of the carton blank will be avoided. Further, the location of the vacuum cups on the carton blank is more precise and the chances of a faulty delivery of a squared blank from the rotary placer to the assembly position is lessened.
Some rotary devices use a cam surface to reciprocate the vacuum cups at the pick and place positions and thereby effectuate straight line motion. However, the problem with many of these devices is that they do not rotate continuously since they have to stop at the pick and place positions to permit the vacuum cups to reciprocate. Thus, these devices are slower and less efficient than continuously rotating devices.
Since it is desirable that the rotary placer be continuously moving when effectuating a pick from the magazine and since it is also desirable that the pick occur using straight line motion, some devices include gear assemblies and cam tracks to reciprocate the vacuum cups and to move the vacuum cups linearly outward at the pick position. The cam track causes a shaft mounting the vacuum cups to swing in a direction opposite to the direction of rotation of a rotating turret and at the same time matching the speed of the turret thereby effectuating straight line motion of the vacuum cups as the rotary placer is rotating.
Other devices imparting linear motion of the vacuum cups during continuous rotary motion of the placer which are cheaper and easier to manufacture, and which are more efficient and more reliable to operate are similarly desirable.